Demi Lovato is showing her dark and light sides in her just-released video for "Heart Attack." But, by all accounts, what she showed on set was even more impressive.

MTV News spoke to director Chris Applebaum, who revealed that while shooting the clip for [article id="1704949"]"Heart Attack,"[/article] Lovato did something that he's only seen Celine Dion do before her: sing live.

"I do also want to note that in 20 years of directing music videos, I have seen every single artist lip-sync to their video with the exception of two people. One was Celine Dion, who said, 'If you don't do that, you sing so that people can see your throat move and people can feel the emotion.' And two, it was Demi Lovato," he revealed. "Demi is the real deal. People felt it when they were around her."

He added, "Her performance is very interesting. I've worked with some of the biggest artists in the world, multiple times, and Demi is a really unique performer. She's extremely emotional. She's extremely complicated, wonderful, amazing, beautiful girl with a huge heart and conflicts within herself that she's dealing with very openly. And I feel like her performances are the visual equivalent of taking all of that, throwing it into a can of soda and shaking it up so that when you pull the top everything kind of explodes."

Indeed, Lovato explodes in the clip, clenching her fists and grimacing as she squeezes out raw emotion. The singer covers herself in black paint, as if she were masking her innocent, natural glow brought on by talking to her crush. She doesn't allow herself to fall in love, and the thick, black ink guards her from heartbreak. In other shots, she rocks out with her band. Wearing a dark, sheer top and smoky eyes, she belts out the song, leaving her fresh face behind.

"The song is about this kind of duality that Demi faces," he explained. "She's singing about really wanting to fall in love. But then also really wanting to make sure she holds herself back a little bit, so she doesn't get hurt. She constantly is singing about this duality throughout the song. It's like a push and pull where we tried to metaphorically represent those two sides by having two metaphorically different sides of Demi," he explained about the visual.

He added, "There's the angelic white. First you see Demi pictured in this more angelic white performance where these darker black elements start creeping into the frame almost ready to take over her. And then you also see her, the polar opposite, a black set-up where there's some white or good, I don't want to say good or evil, or good or bad, there's just sort of these opposites. You see her in this black environment where these forces of white, the opposite, are still present and creeping in."

While the clip doesn't favor elaborate storytelling to make its point, it does put Demi's heart and soul on display. "For her, it's a basic performance video; it's classic Demi," he said, before stumping for the art of the performance video. "Like, people want to see their artists; they want to see performances. Demi, we really tapped into those things that are unique about her, and unique about her as a performer to propel her viewers and her fans into the emotional core of the song."

"Heart Attack" is the lead single off her May 14 album release, [article id="1704675"]Demi.[/article]

Which of Demi's "Heart Attack" looks do you like best? Tell us everything in the comments!